[Bony bridges of the lumbar transverse processes]

A traumatic osseous bridge between lumbar transverse processes is a bone formation occurring after severe or even mild trauma of the back. However, only few of the patients with a contusion of the back or a fracture of a lumbar transverse process develop such an osseous bridge. The localisation of the haematoma plays an important role in this process, but myositis ossificans is a mandatory condition. Anamnesis will not lead to traumatic aetiology in all cases, because sometimes the patient is not aware of the fact that a transverse process has been fractured. The diagnosis finally depends on the recognition of the different shapes. The traumatic osseous bridge is characterised by the kind of trauma that causes the fracture of the transverse process. The shapes can be classified as "h", "H", "K", or "Z". Among 72 patients with inter-transverse osseous bridges, only 11 patients have congenital bridges. The congenital osseous bridge shows typical features that can be explained by means of embryogenic and functional dynamic considerations. These symptoms are the O-shape, concavity of the lumbar spine of a pathological nature and the absence of degenerative changes in the corresponding intervertebral space.